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Mike from Gideon Optics adjusting elevation on Guardian LPVO

Guide to Parallax Error and Adjustment

If you want to get better accuracy out of your scoped rifle, making the manual scope parallax adjustments you need to keep your aiming point zeroed is vital. Parallax error is caused by the curved lenses used in your optics. This causes an image distortion that makes it appear you’re on target when you’re not. You can make every shot count by understanding where your firearm’s optic is parallax-free and how to adjust your aiming at other ranges to account for the curvature of your lens.

Seeing What Isn’t There

As light enters your scope, curved lenses collect it, flip it, magnify it, flip it again, and finally projects it out the eyepiece to your eyeball. As it passes through these lenses, the image distorts, with the greatest amount of parallax error appearing toward the edge of the image and the least in the center. Manufacturers engineer scopes to be parallax-free at a set range or offer an adjustable parallax range set by the shooter.  

Identifying Parallax Error

View of Guardian LPVO reticle at 1x and 10x

When you sight down your scope, ideally, the reticle should be centered and aimed for precise shot placement on your target. Scope parallax adjustment lets you set a range at which parallax is minimized so that slight eye movements that take the reticle out of center will remain placed right where you put it on your target. When there is no movement of the reticle to a different aiming point as your eye moves, you’ve found your parallax-free range.

To identify if you need to adjust for parallax error, look through the scope, center your reticle in the middle of your field of view, and aim at your target. Now, allow your eye to move slightly while holding the gun steady. If the reticle changes position, moving away from the point you were aiming at, your target’s range makes scope parallax adjustment necessary for accuracy.

Fixed Vs. Adjustable Parallax

Optics manufacturers engineer their scopes with one of two ways for shooters to manage parallax. The first way is by offering an adjustable parallax that the shooter can change in the field using an adjustment knob. Turning the knob moves a lens inside your scope to change its parallax range, bringing the reticle into sharper focus and removing the distortion caused by parallax error. 

Fixed parallax scopes are set to be parallax-free at a certain yardage. In the case of the new-for-2024 Guardian LPVO scope line, 100 yards gives you accurate shooting with no parallax distortion. This range maximizes the Guardian’s accuracy for mid-range target engagement, especially with the AR-15, which is optimally zeroed for 100/300 yards. Only minimal parallax will be encountered unless you’re shooting at a target significantly closer or farther away than 100 yards. 

While adjustable parallax scopes allow for more flexible precision, that flexibility comes at a cost, both monetary and in terms of reliability. More moving parts increase the cost of engineering, production, and quality testing while also introducing more features that can fail in the field. Fixed parallax scopes can be just as accurate in the hands of a shooter who has trained to make the most of their optic, be more reliable, and come at a sizable discount compared to adjustable scopes. 

Manual Scope Parallax Adjustments with a Fixed Parallax Scope

Mike from Gideon Optics testing the Guardian LPVO at an outdoor shooting range

Adjusting for scope parallax with a fixed parallax scope is a relatively easy skill to learn, but it takes time and practice to ingrain it in your shooting habits and muscle memory. Getting started is as easy as zeroing your scope.

  1. Zero Your Scope at Parallax-Free Yardage – It’s important to sight in your scope for optimal accuracy and become familiar with using it at the 100-yard range where parallax error isn’t a factor.
  2. Move to a Range That Requires a Parallax Scope Adjustment – Moving to a 200-yard target will let you work with adjusting for the parallax on your Guardian while also putting you at the highest point of a bullet trajectory on rifles for 100/300-yard battlesight zero.
  3. Sight Down Your Scope – Position the reticle dead center of your scope. There may be blurring around the edges of your image where the parallax distortion is greatest. Use this distortion to help your aim by making the blurred ring equal all the way around the outside of the sight picture. 
  4. Squeeze Your Trigger and use a Spotter or Scope – Check your accuracy after firing a shot and make the necessary adjustments to your aim point. While keeping the reticle centered and parallax distortion equal should keep you pretty close to on-target, fine-tuning your aim may be required.
  5. Practice at Range, Then Switch It Up – Take some time to get comfortable shooting with your manual scope parallax adjustments, then shift to a new range position. Repetition builds habits. When shooting, that means accurate shot placement and precise groupings.
  6. Make Parallax Adjustments Second Nature – Compensating for a scope’s parallax error isn’t a one-and-done training session. It takes ongoing work to develop the skill and regular practice to keep it. Your adjustment also may vary from scope to scope, so be sure to put in the range time on the weapon you’re using.

Get a Precision Scope for Your Rifle

The Guardian LPVO line of precision optics gives you a variable magnification scope that’s parallax-free at 100 yards with either an FFP or SFP reticle to meet your shooting needs and is priced to meet your budget. This makes it the practical choice for hunting, varminting, and tactical rifles and carbines. Sign up for our email list to get new product information sent directly to you. Order a scope for your customized firearm from Gideon Optics today.

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